Tanning



ADOLF ROMER, or s'ru'rrean'r,

A CORPORATION OF DELAWARE AND Louis ASSIGNORS, IBY MESNE ASSIGNMENTS, TO- THE CHEMICAL ronnna'rron, 1 w,

ATe-r oF-mr';

BLANonY, or MANNHEIM, GERMANY,

v TANNING. 1,414,045 Specification of Letters Patent, 1i Drawing.

To all whom it may concern:

Be it known that we, AnoLr' Roman and LOUIS BLANGEY, citizens of the German Empire and of the Swiss Republic, respectively, residingr respectively, erInany, have invented new and useful Improvements in Tanning, of

specification.

terials employed for tanning hides Without exception possess an amorphous character.

We have now found that we can transform hides into a valuable leather by means ofcrystalline water-solubleorganic bodies contaming an acid group such assulfonic or carboxylic acid groups or both'such groups, and capable of precipitating glue or gelatlne from solutions thereof. All such bodies can be used either alone or together with natural or synthetic tanning materials of other kind or mixed with non-tanning materials.

The process of tanning with the aid of substances of the aforesaid character can be carried out in watery solution in'the usual manner and in order to further illustrate the invention by some examples, We mention in the following a Emample l. Dissolve at ordinary temperature 50 parts of dihydroxy' ditolyl-methane I v on on Q Q C l I Hg (which is obtainable by condensing pa'rahomosaligenine-se Auwers- Berichte .vol. P31 8 hydrocliloric acid and can'be purified by dlstillingthe raw product in vacuo, and represents colorless crystals melting at 126 C.) in 200 parts of su furic acid of 66 B. and allow to stand until a test on dilution with ice-water will' give a clear solution.

Then pour on 400 parts of ice and saturate f at Stuttgart and Mannheim,-

V Chemie vol. 343, p. 85),or of 4.4'-dih 2531-with p-cresol by meansof' with common salt. The sodium salt-0f the sulfonic acid produced is tered off, washed with a solution of common salt, pressed and dried. The solution serving for-the tanning process is prepared by-dissolving the product in water and adding a little sulfuric acid. a

I E wamplc H. p

' Dissolve 268 parts of oz-dinaphthylmethane Grabowski, 'Berichte der Deutschen Chemischen Gesel'lschaft' vol.

ature ofl0 C. with 250 parts of chlorosulfonic acid. When sulfonationis complete, pour the mass into water, separatethe nitroenzine and neutralize the acid solution with barium carbonate.

v Patented Apr. 25, 1922 Application filed September 2. 1916. Serial No. 118,286. 7

thereby precipi-. 'tated in a fine crystalline form. This is fil- 7, p. 1605) in 2000' parts of nitrobenzene and treat at a temper-- The solution ofth barium salt formed is-then filtered when still hot and evaporated while. stirring until crystallization beginsl The barium salt separated out is washed with cold water and transformed into the free 'sulfonic'acid by adding exactl the required quantity of sulfuric acid. 'l hef freesulfonic acid can be obtained in the form oflarge well-shaped crystals by carefully evaporating at (1, finally in vacuo,.-or by precipitating the concentrated aqueous solution with strong hy drochloric acid. The aqueous solution can be employed for tanning directly without adding another acid. I

In quite an analogous manner sulfonic acids of 4.4-dihydroxy-diphenylmethane,

(F. P. 158-160 0.), or of 4.4--dih droxydiphenyl-dimethylmethane (Annal en der I ydroxy- 3.3 --dimethyld1phenyl nnalen der Chemie vol.

henylmethane can beprepared which sul onic acids separate, out after evaporating the aqueous solutions, for some time, in watery solution of for tanning.

a crystalline form; the the crystals can be used Sulfon-ic acids of hydroxy-dinaphthylme thane can also be employed.

' Example I I l Dissolve 448 parts of 2.6-naphthol-sul-, onic acid in 2500 parts of sulfuric acid of 'dilnethylmethane 400, p. 33), or of 4.4 dihydroxy -'3.3' dimiethyl-di at once or when allowed to stand A tanning bath is prepared while using a sulfonic acid as can be prepared bytreating the condensation product of meta-cresol,

para-cresol or alpha-naphthol and acetone (Annalen der Chemie vol. 388, p. 304:; Berichte der Deutschen Chemischen Gresellschaft vol. 25, referate p. 336) with fuming sulfuric acid or chlorosulfonic acid, or by treating for several hours on the water-bath 128 parts of 4.4:-dihydroxy-3.3 dimethyldiphenyl-dimethylmet-hane with 252 parts of crystallized sodium sulfite dissolved'in 1000 parts 'of'water and 100 parts of 30% formaldehyde.

Example V. v Dissolve 228 parts of 6.6-dihydroxy-3.3-

dimethyl-diphenylmethane in 1200 parts of I nitrobenzene and add slowly, at a temperasulfonic acid. Allow to stand for 3 to t hours, then drive out the hydrogen chlorid.

dissolved and extract the sulfonic acid from its solution in nitrobenzene by shaking with water. The aqueous solution obtained can be directly employed for tanning, or if desired the sulfonic acid can be precipitated therefrom by evaporating and saturating with gaseous hydrochloric acid.

A tanning solution is prepared with'the aid of a disulfonic acid obtained-as follows: Dissolve 168 parts of para-cresol-dial'cohol in 1000 parts of para-cresol, then add 25 parts of concentrated hydrochloric acid. The temperature will risesomewhat and on cooling the condensation product formed crystallizes out and can be completely precipitated by adding gasoline. lite-crystallized from glacial acetic acid the'product has the F. P. 215- C. 87 parts of time prod not are suspended in 400 parts of nitrobenzene and 59 parts of chlorosulfonic acid are added, whilst stirring and cooling with ice. The disulfonic acid formed will soon v separatein the form of small needles.

Example VII. Treat hides in the usual way with an aqueous solution of -5.5'-dihydroxy-2.2-dinaphthylamine-7.7-disulfonic acid (obtainable according to example 2 of German Letters Patent No. 114,974)

ture of from 0 to 5 (1., 117 parts of chlorog intense Example VH1 50 parts of 4.4L-dihydroxy-benzophenone (Annalen der Chemie vol. 218, p. 354) are dissolved in 200 parts of sulfuricacid monohydrate, then 150 parts of fuming sulfuric acid containing 23% S0 are added and the mixture is stirred at ordinary temperature, until a test portion is clearly soluble in water. The sulfonicacid can be obtained in a pure free state by decomposin its barium salt by the required quantity 0 sulfuric acid; the aqueous solution thereof can be used directly for tanning.

Example IX.

Treat hides in the usual way with an aqueous solution of anthraquinone-beta-sul- .fonic or- 2.6-disulfonic acid or 1.4-dichloroanthraquinone sulfonic acid, or hydroxyor nitro-anthraquinone sulfonic acids or naphthanthraquinone sulfonic acids or with the respective salts in the presence of acid.

lVhile compounds such as the afore-described, possessing the above. stated characteristic propertiesmnd containing in their molecule more than one aromatic nucleus connected by one or more polyvalent atoms, are particularly suitable for the claimed process, other crystalline water-soluble aromatic compounds containing sulfonic or carboxylic acid groups and capable of precipitating glue, or gelatine, solutions are also suitable for the purpose of the present invention. Instances of such compounds are naphtholor naphthylamine sulfonic acids capable of preci itating glue, such as 1.4- naphthol sulfonic acid, 2.6-naphthol-sultonic acid, 1.2.4- or 2.1.5- naphthylamine-disulfonic acids, etc.

The following rocedure sets' forth an illustrative embod ment of a manner in which my invention may be carried into practice:

100 parts of the sulphonate prepared as set forth in Example I may be dissolved in 1600 parts of water, to which may be added about 7 5 parts of dilute sulphuric acid having strength of about 10%, the hides having been Well limed and bated, are introduced into the vat containing a solution as prepared above and are allowed to remain in the vat for a period of from 8 to 12 days.

The leather thus obtained is subsequently dried and treated with fat in the usual manner.-

We claim 1. The process of tanning which comprises treating hide in a loath containing an aromatic sulfonic acid derived from an aromatic hydrocarbon containing within its molecule at least two aromatic nuclei, said nuclei being united by at least one polyvalent atom.

2. The process of tanning which com- 'fonated derivative of united by at least one carbon sulfonated derivatlve of dihydroxy-dito methane. p

5. The processof tanning Which comprises treating hide in a bath containing a dihydroxy-ditolyl sulfonate and sulfuric acid.

6. A tanning substance comprising a'sulan aromatic hydrocarbon containing within its molecule at least two aromatic nuclei united by at least one polyvalent atom, said derivative-being solu 'ble in water, capable of precipitating glue from solution, structure.

7. A tanning substance comprlslng a suland having a crystalline fonated derivative'of an aromatic hydrocarbon containing within its molecule at leasttwo aromatic nuclei united by at least one least. two aromatic nuclei, said,

carbon atom, said derivative in water, capable of precipitating glue from solution, and having a crystalline structure.

8. A tanning substance comprising a sulfonated derivative of a diarylmethane, said derivative being soluble in water, capable of precipitating glue fromsolution, and having a crystalline structure.

9. A tanning substance comprising a sulfonated derivative of dihydroxy-ditolylmethane, said derivative being soluble in being soluble water, capable of precipitating glue from solution, and having a crystalline structure.

lxlfA tanning-substance comprising a dihydroxy-ditolylmethane sulfonate, being soluble in water, capable of preclpitating glue from solution, and having a crystalline structure.

In testimony whereof we have hereunto set our hands in the presence of subscribing witnesses.

- DR; ADOLF ROMER.

LOUIS BLANGEY. Witnesses as to Dr. Adolf Romer:

F RIDA KLAI ER, PAULINE Mt'iLLER.

Witnesses as to Louis Blangey ARTHUR DENONVILLE, RUTH P. MANN. 

